Metal Roofing 101

If you own a home and have had to replace shingles in the past, then you know the pain of owning a home involves replacing the asphalt shingles every 10-15 years. Wouldn't you like to install an efficient and long lasting material that you only have to do once? With metal roofing, you can! Metal roofing can last over 100 years, it looks attractive and rarely needs repairs--that is, if it's done correctly. Use this guide to metal roofing and you'll be sure to make an informed decision next time you're in the market for a new roof.

Residential Systems

There are two basic styles of metal roofing systems for residential use:

• · Exposed Fasteners

• · Concealed Fasteners

Exposed fastener systems are typically layered one on top of the other with an exposed screw or nail that is sealed to the metal roof with a butyl grommet or an aluminum covered nail head. These systems are set up to be the easiest and cheapest methods for installing a metal roof. They may require some maintenance in the coming decades as nails and screws tend to work their way back out when the constant expansion and contraction occur during the day and night.

Concealed fastener systems are installed with clips that are screwed to the subroof on one side of the panel. The next sheet of metal roofing then overlaps and hooks onto the clip, covering the screw in the process. A clip is secured and screwed to the other side of the panel and the process is repeated down the roof. These roofing systems are more time consuming to install and are therefore more expensive.

Materials

Typically, there are two types of materials that are used in metal roofing:

• · Galvanized steel

• · Galvalume

Galvanized steel is commonly coated with zinc to prevent corrosion and rust. Galvalume is a galvanized aluminum that is powder coated or painted with a zinc based paint to prevent corrosion. While these two materials dominate the residential field, there are a few exceptions. Zinc, copper, stainless steel and aluminum are just a few examples of alternative metal roofing materials that can be used on residential projects. These materials are much more expensive in both material costs and labor.

Grades

Metal roofing comes in particular grades that are defined by the thickness of the metal and by the amount of paint, zinc or galvanized coating is applied to the material. For galvanized steel, the minimum rating for a residential structure is nominally G-60. For Galvalume, minimum grades for residential use should be an AZ50 or greater. AZ55 is typically the optimal range for residential use that's affordable and long lasting. Other grades with reflective UV coating and baked enamel paints can cost significantly more than cheaper grades. Just remember, you get what you pay for when it comes to metal roofing.